Fiber-reinforced polymeric resin composite materials are becoming more widely used in aircraft structures due to their strength to weight characteristics. Current fastening methods for securing composite parts together can require relatively complicated tooling and procedures. For example, titanium fasteners have been used to secure composite parts but such fasteners are relatively expensive. Also, due to the material and mechanical properties of composite materials, the use of titanium rivets requires advanced drilling techniques to avoid or minimize stress concentrations in the composite parts. Alternatively, the use of aluminum rivets may not be appropriate for securing parts made of composite materials due to compatibility issues that may result in galvanic corrosion between the aluminum and carbon in the composite material.
For aircraft applications, the use of electrically conductive metallic fasteners in composite materials with a very low electrical conductivity can also cause some concerns associated with electromagnetic interference (EMI) and lightning strike protection.
Improvement is therefore desirable.